Men, women really do have big personality differences

If men and women at times seem to be from different planets, it may be because there are large differences in their personalities, a new study suggests.

The results show that about 18 percent of women share similar personalities with men, and 18 percent of men share similar personalities with women. But the majority of women have personality traits that are quite distinct from those of men, and vice versa, the researchers say.

Men tend to be more dominant (forceful and aggressive) and emotionally stable, while women tend to be more sensitive, warm (attentive to others) and apprehensive, the study found.

"Psychologically, men and women are almost a different species," said study researcher Paul Irwing, of the University of Manchester, in the United Kingdom.

The new findings may explain why some careers are dominated by men (such as engineering) and others by women (such as psychological sciences), Irwing said.

"People self-select in terms of their personality… and what they think is going to be suitable in terms of the fit," for their career, Irwing said.

However, the paper, published today (Jan. 4) in the journal PLoS ONE, has drawn criticism from others in the field who argue the methods the researchers used for computing their results are flawed, and that men and women are not so dissimilar after all.

Irwing and colleagues analyzed information from more than 10,000 people in the United States between the ages of 15 and 92 who took a personality test. The tests were designed to measure 15 personality facets, including warmth, emotional stability, dominance, liveliness, social boldness, sensitivity and openness to change.

The researchers then combined the scores on these personality facets to compute what they call the "global difference" in personality between men and women. The "global difference," is essentially a sum of all the differences.

Previous studies have underestimated how much the sexes actually differ because they have instead computed the average score, said study researcher Marco Del Giudice, of the University of Turin in Italy.

But the findings counter the prevailing view among psychologists that, on the whole, men and women are more similar than they are different, in a number of ways, including personality traits.

Janet Shibley Hyde, a professor of psychology and women's studies at the University of Wisconsin who published a paper in 2005 that was influential in contributing to this hypothesis, said the new study does not overturn this view.

For starters, the men and women in the study assessed their own personality traits. People may be inclined to rate themselves in a way that conforms with gender stereotypes, Hyde said. "It's not very manly to say that you're sensitive," she said.

Hyde also said using the 15 personality facets to compute a "global difference" gives you a value that doesn't have any actual meaning.

Patrick Ian Armstrong, a professor of psychology at Iowa State University, agreed with Hyde's assessment. Armstrong pointed out that the "global difference" value will actually get bigger the more personality factors the researchers consider (so analyzing 15 factors will show a greater difference than analyzing five factors.)

Given the issues with the study's methods, "it's not as open and shut a case as they make it out to be," Armstrong said. "The questions they're trying to answer are probably still worth asking," Armstrong said.